Answer:
1.25sec
Step-by-step explanation:
#let the vertical position affected by gravity be [tex]s(t)[/tex] and [tex]v_0=0[/tex] be the initial velocity:
[tex]s(t)=-16t^2+v_0t+h_o \ \ \ h_o=25\\\\=-16t^2+0t+25\\\\=-16t^2+25\\\\16t^2=25\\\\t=\sqrt{1.56}=1.25[/tex]
#we only consider a positive time since we are moving forward. Hence it takes 1.25seconds to land on the ground.
